hi graham,
>It seems to me that knowing about the efficiency of layout table filtering is critical to arguments of the form "harmful summaries on layout tables are not >problematic because UAs filter them out".
Demo version of jaws and window eyes are available for download and we
have plenty of URLs with layout tables and summary attributes. So I am
sure you could test the veracity of the claim "harmful summaries on
layout tables are not problematic because UAs filter them out" if you
feel it is critical to the summary debate.
regards
steve
2009/6/30 James Graham <jgraham@opera.com>:
> Steven Faulkner wrote:
>>
>> not that I know of, commercial vendors AT are the opposite of open.
>> They consider what's under the hood of their products to be commercial
>> secrets. To understand much of how AT behave and what they support,
>> reverse engineering is required. Which is what myself and others have
>> done for many behaviours.
>> I haven't done so for their table filtering as I have other testing
>> prioties (ie ARIA) and also don't consider that it will make a
>> difference in this particular debate whether the algorithm is
>> understood or not.
>
> It seems to me that knowing about the efficiency of layout table filtering
> is critical to arguments of the form "harmful summaries on layout tables are
> not problematic because UAs filter them out". This does not imply that the
> exact algorithm must be known, but it does imply that the various
> probabilities like P(table is identified as a layout table | table is a
> layout table), P(table is identified as a data table | table is a layout
> table), and so on, are necessary to know what
>
> As it happens, Mozilla have an open source layout table detection algorithm
> [1] which is rather simple. Sadly it needs computed style (and hence a
> browser) to fully implement. This makes it harder to run in an automated way
> over a large set of tables.
>
> [1]
> http://mxr.mozilla.org/mozilla/source/accessible/src/html/nsHTMLTableAccessible.cpp#1033
>
--
with regards
Steve Faulkner
Technical Director - TPG Europe
Director - Web Accessibility Tools Consortium
www.paciellogroup.com | www.wat-c.org
Web Accessibility Toolbar -
http://www.paciellogroup.com/resources/wat-ie-about.html